Ranging is a process or method to determine the distance from one position to another position.
Ranging is the term merely applying for distance metering with moving objects. Commonly used term for residing terrestrial objects is surveying.
Classical active ranging systems are operating with unilateral transmission and passive reflections, as SONAR, RADAR and LIDAR. Further development led to cooperative systems, where both positions are equipped with respective apparatus and thus provide bilateral measuring.
Even more challenging are the approaches where ranging is obtained from passive measurements only, hence the signature of the object is generating the signal that is computed for range. However such measurements requires multiple measurements to obtain range, otherwise the system is just capable to provide bearings from sole measurements.